In the specification of our earlier South African Patent No 90/6421 entitled "Underwater Cleaning Apparatus" we described a cleaning apparatus of the type having a flexible circular member which surrounds the inlet to a chamber in a body for the apparatus. On the opposite side of the chamber to the inlet are two substantially co-planar outlets which lead to two passages. These passages combine at a position remote from the outlets and are connected to a flexible suction hose in known manner.
Within the chamber is a closure arrangement for alternately closing and opening the outlets to interrupt the water flow in the passages and cause the apparatus to move over a surface to be cleaned. This way of effecting movement of apparatuses of this type is well-known.
The closure arrangement comprises a pivotable body having two closures provided by two flat surfaces extending at an angle of about 145.degree. to each other (although this angle may vary considerably) and having the pivot point near the apex formed by the surfaces. The body includes a curved surface extending between the flat surfaces, the curved surface fulfilling a function of directing water flow to one side or other of the body depending on which outlet is open.
A problem encountered in the above configuration is that it is sometimes difficult for large physical bodies to pass through the chamber without obstructing or being caught by the closure arrangement.
An object of this invention is to provide a closure arrangement which allows for the improved passage of bodies through the chamber.